Gemini Project
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Project Gemini () was NASA's second
human spaceflight Human spaceflight (also referred to as manned spaceflight or crewed spaceflight) is spaceflight with a crew or passengers aboard a spacecraft, often with the spacecraft being operated directly by the onboard human crew. Spacecraft can also be ...
program. Conducted between projects
Mercury Mercury commonly refers to: * Mercury (planet), the nearest planet to the Sun * Mercury (element), a metallic chemical element with the symbol Hg * Mercury (mythology), a Roman god Mercury or The Mercury may also refer to: Companies * Merc ...
and Apollo, Gemini started in 1961 and concluded in 1966. The Gemini spacecraft carried a two-astronaut crew. Ten Gemini crews and 16 individual astronauts flew low Earth orbit (LEO) missions during 1965 and 1966. Gemini's objective was the development of space travel techniques to support the Apollo mission to land astronauts on the Moon. In doing so, it allowed the United States to catch up and overcome the lead in
human spaceflight Human spaceflight (also referred to as manned spaceflight or crewed spaceflight) is spaceflight with a crew or passengers aboard a spacecraft, often with the spacecraft being operated directly by the onboard human crew. Spacecraft can also be ...
capability the Soviet Union had obtained in the early years of the Space Race, by demonstrating: mission endurance up to just under 14 days, longer than the eight days required for a round trip to the Moon; methods of performing
extra-vehicular activity Extravehicular activity (EVA) is any activity done by an astronaut in outer space outside a spacecraft. In the absence of a breathable Earthlike atmosphere, the astronaut is completely reliant on a space suit for environmental support. EVA inc ...
(EVA) without tiring; and the
orbital maneuver In spaceflight, an orbital maneuver (otherwise known as a burn) is the use of propulsion systems to change the orbit of a spacecraft. For spacecraft far from Earth (for example those in orbits around the Sun) an orbital maneuver is called a ' ...
s necessary to achieve rendezvous and docking with another spacecraft. This left Apollo free to pursue its prime mission without spending time developing these techniques. All Gemini flights were launched from
Launch Complex 19 Launch Complex 19 (LC-19) is a deactivated launch site on Cape Canaveral Space Force Station, Florida used by NASA to launch all of the Gemini crewed spaceflights. It was also used by uncrewed Titan I and Titan II missiles. LC-19 was in use fro ...
(LC-19) at Cape Kennedy Air Force Station in Florida. Their launch vehicle was the Gemini– Titan II, a modified
Intercontinental Ballistic Missile An intercontinental ballistic missile (ICBM) is a ballistic missile with a range greater than , primarily designed for nuclear weapons delivery (delivering one or more thermonuclear warheads). Conventional, chemical, and biological weapons c ...
(ICBM). Gemini was the first program to use the newly built Mission Control Center at the Houston Manned Spacecraft Center for
flight control A conventional fixed-wing aircraft flight control system consists of flight control surfaces, the respective cockpit controls, connecting linkages, and the necessary operating mechanisms to control an aircraft's direction in flight. Aircraft e ...
. The astronaut corps that supported Project Gemini included the " Mercury Seven", " The New Nine", and " The Fourteen". During the program, three astronauts died in air crashes during training, including both members of the prime crew for Gemini 9. This mission was flown by the backup crew. Gemini was robust enough that the United States Air Force planned to use it for the
Manned Orbital Laboratory The Manned Orbiting Laboratory (MOL) was part of the United States Air Force (USAF) human spaceflight program in the 1960s. The project was developed from early USAF concepts of crewed space stations as reconnaissance satellites, and was a succ ...
(MOL) program, which was later canceled. Gemini's chief designer,
Jim Chamberlin James Arthur Chamberlin (May 23, 1915 – March 8, 1981) was a Canadian engineer who contributed to the design of the Canadian Avro Arrow, NASA's Gemini spacecraft and the Apollo program. In addition to his pioneering air and space efforts, he ...
, also made detailed plans for cislunar and lunar landing missions in late 1961. He believed Gemini spacecraft could fly in lunar operations before Project Apollo, and cost less. NASA's administration did not approve those plans. In 1969, McDonnell-Douglas proposed a " Big Gemini" that could have been used to shuttle up to 12 astronauts to the planned space stations in the Apollo Applications Project (AAP). The only AAP project funded was Skylab – which used existing spacecraft and hardware – thereby eliminating the need for Big Gemini.


Pronunciation

The constellation for which the project was named is commonly pronounced , the last syllable rhyming with ''eye''. However, staff of the Manned Spacecraft Center, including the astronauts, tended to pronounce the name , rhyming with ''knee''. NASA's public affairs office issued a statement in 1965 declaring "Jeh-mih-nee" the "official" pronunciation. Gus Grissom, acting as Houston
capsule communicator Flight controllers are personnel who aid space flight by working in such Mission Control Centers as NASA's Mission Control Center or ESA's European Space Operations Centre. Flight controllers work at computer consoles and use telemetry to mon ...
when Ed White performed his spacewalk on Gemini 4, is heard on flight recordings pronouncing the spacecraft's call sign "Jeh-mih-nee 4", and the NASA pronunciation is used in the 2018 film '' First Man''.


Program origins and objectives

The Apollo program was conceived in early 1960 as a three-man spacecraft to follow Project Mercury.
Jim Chamberlin James Arthur Chamberlin (May 23, 1915 – March 8, 1981) was a Canadian engineer who contributed to the design of the Canadian Avro Arrow, NASA's Gemini spacecraft and the Apollo program. In addition to his pioneering air and space efforts, he ...
, the head of engineering at the Space Task Group (STG), was assigned in February 1961 to start working on a bridge program between Mercury and Apollo. He presented two initial versions of a two-man spacecraft, then designated Mercury Mark II, at a NASA retreat at Wallops Island in March 1961. Scale models were shown in July 1961 at the McDonnell Aircraft Corporation's offices in St. Louis. After Apollo was chartered to land men on the Moon by President John F. Kennedy on May 25, 1961, it became evident to NASA officials that a follow-on to the Mercury program was required to develop certain spaceflight capabilities in support of Apollo. NASA approved the two-man / two-vehicle program rechristened Project Gemini (Latin for "twins"), in reference to the third constellation of the Zodiac with its twin stars Castor and Pollux, on December 7, 1961. McDonnell Aircraft was contracted to build it on December 22, 1961. The program was publicly announced on January 3, 1962, with these major objectives: * To demonstrate endurance of humans and equipment in spaceflight for extended periods, at least eight days required for a Moon landing, to a maximum of two weeks * To effect rendezvous and docking with another vehicle, and to maneuver the combined spacecraft using the propulsion system of the target vehicle * To demonstrate
Extra-Vehicular Activity Extravehicular activity (EVA) is any activity done by an astronaut in outer space outside a spacecraft. In the absence of a breathable Earthlike atmosphere, the astronaut is completely reliant on a space suit for environmental support. EVA inc ...
(EVA), or space-"walks" outside the protection of the spacecraft, and to evaluate the astronauts' ability to perform tasks there * To perfect techniques of atmospheric reentry and touchdown at a pre-selected location on land


Team

Chamberlin designed the Gemini capsule, which carried a crew of two. He was previously the chief aerodynamicist on
Avro Canada Avro Canada was a Canadian aircraft manufacturing company. It was founded in 1945 as an aircraft plant and within 13 years became the third-largest company in Canada, one of the largest 100 companies in the world, and directly employing over 5 ...
's Avro Arrow fighter interceptor program. Chamberlin joined NASA along with 25 senior Avro engineers after cancellation of the Canadian Arrow program, and became head of the U.S. Space Task Group's engineering division in charge of Gemini. The prime contractor was McDonnell Aircraft Corporation, which was also the prime contractor for the Project Mercury capsule. Astronaut Gus Grissom was heavily involved in the development and design of the
Gemini spacecraft Project Gemini () was NASA's second human spaceflight program. Conducted between projects Mercury and Apollo, Gemini started in 1961 and concluded in 1966. The Gemini spacecraft carried a two-astronaut crew. Ten Gemini crews and 16 individual ...
. What other Mercury astronauts dubbed "Gusmobile" was so designed around Grissom's 5'6" body that, when NASA discovered in 1963 that 14 of 16 astronauts would not fit in the spacecraft, the interior had to be redesigned. Grissom wrote in his posthumous 1968 book ''Gemini!'' that the realization of Project Mercury's end and the unlikelihood of his having another flight in that program prompted him to focus all his efforts on the upcoming Gemini program. The Gemini program was managed by the Manned Spacecraft Center, located in
Houston, Texas Houston (; ) is the most populous city in Texas, the most populous city in the Southern United States, the fourth-most populous city in the United States, and the sixth-most populous city in North America, with a population of 2,304,580 in ...
, under direction of the Office of Manned Space Flight, NASA Headquarters, Washington, D.C. Dr.
George E. Mueller George Edwin Mueller (; July 16, 1918 – October 12, 2015), was an American electrical engineer who was an associate administrator at NASA who headed the Office of Manned Space Flight from September 1963 until December 1969. Hailed as one of ...
, Associate Administrator of NASA for Manned Space Flight, served as acting director of the Gemini program. William C. Schneider, Deputy Director of Manned Space Flight for Mission Operations served as mission director on all Gemini flights beginning with Gemini 6A. Guenter Wendt was a McDonnell engineer who supervised launch preparations for both the Mercury and Gemini programs and would go on to do the same when the Apollo program launched crews. His team was responsible for completion of the complex pad close-out procedures just prior to spacecraft launch, and he was the last person the astronauts would see prior to closing the hatch. The astronauts appreciated his taking absolute authority over, and responsibility for, the condition of the spacecraft and developed a good-humored rapport with him.


Spacecraft

NASA selected McDonnell Aircraft, which had been the prime contractor for the Project Mercury capsule, in 1961 to build the Gemini capsule, the first of which was delivered in 1963. The spacecraft was long and wide, with a launch weight varying from . The Gemini crew capsule (referred to as the Reentry Module) was essentially an enlarged version of the Mercury capsule. Unlike Mercury, the retrorockets, electrical power, propulsion systems, oxygen, and water were located in a detachable Adapter Module behind the Reentry Module. A major design improvement in Gemini was to locate all internal spacecraft systems in modular components, which could be independently tested and replaced when necessary, without removing or disturbing other already tested components.


Reentry module

Many components in the capsule itself were reachable through their own small access doors. Unlike Mercury, Gemini used completely solid-state electronics, and its modular design made it easy to repair. Gemini's emergency launch escape system did not use an escape tower powered by a
solid-fuel rocket A solid-propellant rocket or solid rocket is a rocket with a rocket engine that uses solid propellants ( fuel/oxidizer). The earliest rockets were solid-fuel rockets powered by gunpowder; they were used in warfare by the Arabs, Chinese, Persian ...
, but instead used aircraft-style ejection seats. The tower was heavy and complicated, and NASA engineers reasoned that they could do away with it as the Titan II's
hypergolic propellant A hypergolic propellant is a rocket propellant combination used in a rocket engine, whose components spontaneously ignite when they come into contact with each other. The two propellant components usually consist of a fuel and an oxidizer. Th ...
s would burn immediately on contact. A Titan II booster explosion had a smaller blast effect and flame than on the cryogenically fueled Atlas and Saturn. Ejection seats were sufficient to separate the astronauts from a malfunctioning launch vehicle. At higher altitudes, where the ejection seats could not be used, the astronauts would return to Earth inside the spacecraft, which would separate from the launch vehicle. The main proponent of using ejection seats was Chamberlin, who had never liked the Mercury escape tower and wished to use a simpler alternative that would also reduce weight. He reviewed several films of Atlas and Titan II ICBM failures, which he used to estimate the approximate size of a fireball produced by an exploding launch vehicle and from this he gauged that the Titan II would produce a much smaller explosion, thus the spacecraft could get away with ejection seats. Maxime Faget, the designer of the Mercury LES, was on the other hand less-than-enthusiastic about this setup. Aside from the possibility of the ejection seats seriously injuring the astronauts, they would also only be usable for about 40 seconds after liftoff, by which point the booster would be attaining Mach 1 speed and ejection would no longer be possible. He was also concerned about the astronauts being launched through the Titan's exhaust plume if they ejected in-flight and later added, "The best thing about Gemini was that they never had to make an escape." The Gemini ejection system was never tested with the Gemini cabin pressurized with pure oxygen, as it was prior to launch. In January 1967, the fatal Apollo 1 fire demonstrated that pressurizing a spacecraft with pure oxygen created an extremely dangerous fire hazard. In a 1997 oral history, astronaut
Thomas P. Stafford Thomas Patten Stafford (born September 17, 1930) is an American former Air Force officer, test pilot, and NASA astronaut, and one of 24 people who flew to the Moon. He also served as Chief of the Astronaut Office from 1969 to 1971. After grad ...
commented on the
Gemini 6 Gemini 6A (officially Gemini VI-A) With Gemini IV, NASA changed to Roman numerals for Gemini mission designations. was a 1965 crewed United States spaceflight in NASA's Gemini program. The mission, flown by Wally Schirra and Thomas P. Stafford, ...
launch abort in December 1965, when he and command pilot Wally Schirra nearly ejected from the spacecraft: Gemini was the first astronaut-carrying spacecraft to include an onboard computer, the
Gemini Guidance Computer The Gemini Guidance Computer (sometimes Gemini Spacecraft On-Board Computer (OBC)) was a digital, serial computer designed for Project Gemini, America's second human spaceflight project. The computer, which facilitated the control of mission maneu ...
, to facilitate management and control of mission maneuvers. This computer, sometimes called the Gemini Spacecraft On-Board Computer (OBC), was very similar to the
Saturn Launch Vehicle Digital Computer The Launch Vehicle Digital Computer (LVDC) was a computer that provided the autopilot for the Saturn V rocket from launch to Earth orbit insertion. Designed and manufactured by IBM's Electronics Systems Center in Owego, New York, it was one of th ...
. The Gemini Guidance Computer weighed . Its core memory had 4096 addresses, each containing a 39-bit word composed of three 13-bit "syllables". All numeric data was
26-bit In computer architecture, 26-bit integers, memory addresses, or other data units are those that are 26 bits wide, and thus can represent unsigned values up to 67,108,863. Two examples of computer processors that featured 26-bit memory addressing ...
two's-complement integers (sometimes used as
fixed-point number In computing, fixed-point is a method of representing fractional (non-integer) numbers by storing a fixed number of digits of their fractional part. Dollar amounts, for example, are often stored with exactly two fractional digits, representi ...
s), either stored in the first two syllables of a word or in the accumulator.
Instructions Instruction or instructions may refer to: Computing * Instruction, one operation of a processor within a computer architecture instruction set * Computer program, a collection of instructions Music * Instruction (band), a 2002 rock band from Ne ...
(always with a 4-bit
opcode In computing, an opcode (abbreviated from operation code, also known as instruction machine code, instruction code, instruction syllable, instruction parcel or opstring) is the portion of a machine language instruction that specifies the operat ...
and 9 bits of operand) could go in any syllable. Unlike Mercury, Gemini used in-flight radar and an artificial horizon, similar to those used in the aviation industry. Like Mercury, Gemini used a
joystick A joystick, sometimes called a flight stick, is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. A joystick, also known as the control column, is the principal cont ...
to give the astronauts manual control of
yaw, pitch, and roll An aircraft in flight is free to rotate in three dimensions: '' yaw'', nose left or right about an axis running up and down; ''pitch'', nose up or down about an axis running from wing to wing; and ''roll'', rotation about an axis running from ...
. Gemini added control of the spacecraft's translation (forward, backward, up, down, and sideways) with a pair of T-shaped handles (one for each crew member). Translation control enabled rendezvous and docking, and crew control of the flight path. The same controller types were also used in the Apollo spacecraft. The original intention for Gemini was to land on solid ground instead of at sea, using a Rogallo wing rather than a parachute, with the crew seated upright controlling the forward motion of the craft. To facilitate this, the airfoil did not attach just to the nose of the craft, but to an additional attachment point for balance near the heat shield. This cord was covered by a strip of metal which ran between the twin hatches. This design was ultimately dropped, and parachutes were used to make a sea landing as in Mercury. The capsule was suspended at an angle closer to horizontal, so that a side of the heat shield contacted the water first. This eliminated the need for the landing bag cushion used in the Mercury capsule.


Adapter module

The adapter module in turn was separated into a Retro module and an Equipment module.


Retro module

The Retro module contained four solid-fuel TE-M-385 Star-13E retrorockets, each spherical in shape except for its rocket nozzle, which were structurally attached to two beams that reached across the diameter of the retro module, crossing at right angles in the center. Re-entry began with the retrorockets firing one at a time. Abort procedures at certain periods during lift-off would cause them to fire at the same time, thrusting the Descent module away from the Titan rocket.


Equipment module

Gemini was equipped with an
Orbit Attitude and Maneuvering System The Orbit Attitude and Maneuvering System (OAMS) was a reaction control system used in Earth orbit by the Project Gemini spacecraft. It provided both automatic and manual rotation and translation by means of 16 vernier thrusters using hypergol ...
(OAMS), containing sixteen thrusters for translation control in all three perpendicular axes (forward/backward, left/right, up/down), in addition to attitude control (pitch, yaw, and roll angle orientation) as in Mercury. Translation control allowed changing orbital inclination and altitude, necessary to perform space rendezvous with other craft, and docking with the Agena Target Vehicle (ATV), with its own rocket engine which could be used to perform greater orbit changes. Early short-duration missions had their electrical power supplied by batteries; later endurance missions used the first
fuel cell A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requ ...
s in crewed spacecraft. Gemini was in some regards more advanced than Apollo because the latter program began almost a year earlier. It became known as a "pilot's spacecraft" due to its assortment of jet fighter-like features, in no small part due to Gus Grissom's influence over the design, and it was at this point where the US crewed space program clearly began showing its superiority over that of the Soviet Union with long duration flight, rendezvous, and extravehicular capability. The Soviet Union during this period was developing the Soyuz spacecraft intended to take cosmonauts to the Moon, but political and technical problems began to get in the way, leading to the ultimate end of their crewed lunar program.


Launch vehicle

The Titan II had debuted in 1962 as the Air Force's second-generation ICBM to replace the Atlas. By using hypergolic fuels, it could be stored longer and be easily readied for launch in addition to being a simpler design with fewer components, the only caveat being that the propellant mix ( nitrogen tetroxide and
hydrazine Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly toxic unless handled in solution as, for example, hydrazine ...
) was extremely toxic compared to the Atlas's liquid oxygen/RP-1. However, the Titan had considerable difficulty being man-rated due to early problems with pogo oscillation. The launch vehicle used a radio guidance system that was unique to launches from Cape Kennedy.


Astronauts

Deke Slayton, as director of flight crew operations, had primary responsibility for assigning crews for the Gemini program. Each flight had a primary crew and backup crew, and the backup crew would rotate to primary crew status three flights later. Slayton intended for first choice of mission commands to be given to the four remaining active astronauts of the Mercury Seven: Alan Shepard, Grissom, Cooper, and Schirra. (
John Glenn John Herschel Glenn Jr. (July 18, 1921 – December 8, 2016) was an American Marine Corps aviator, engineer, astronaut, businessman, and politician. He was the third American in space, and the first American to orbit the Earth, circling ...
had retired from NASA in January 1964 and Scott Carpenter, who was blamed by some in NASA management for the problematic reentry of '' Aurora 7'', was on leave to participate in the Navy's
SEALAB SEALAB I, II, and III were experimental underwater habitats developed by the United States Navy in the 1960s to prove the viability of saturation diving and humans living in isolation for extended periods of time. The knowledge gained from the ...
project and was grounded from flight in July 1964 due to an arm injury sustained in a motorbike accident. Slayton himself continued to be grounded due to a heart problem.) Titles used for the left-hand (command) and right-hand seat crew positions were taken from the U.S. Air Force pilot ratings, ''Command Pilot'' and ''Pilot''. Sixteen astronauts flew on 10 crewed Gemini missions:


Crew selection

In late 1963, Slayton selected Shepard and Stafford for Gemini 3, McDivitt and White for Gemini 4, and Schirra and Young for Gemini 5 (which was to be the first Agena rendezvous mission). The backup crew for Gemini 3 was Grissom and Borman, who were also slated for
Gemini 6 Gemini 6A (officially Gemini VI-A) With Gemini IV, NASA changed to Roman numerals for Gemini mission designations. was a 1965 crewed United States spaceflight in NASA's Gemini program. The mission, flown by Wally Schirra and Thomas P. Stafford, ...
, to be the first long-duration mission. Finally Conrad and Lovell were assigned as the backup crew for Gemini 4. Delays in the production of the Agena Target Vehicle caused the first rearrangement of the crew rotation. The Schirra and Young mission was bumped to Gemini 6 and they became the backup crew for Shepard and Stafford. Grissom and Borman then had their long-duration mission assigned to Gemini 5. The second rearrangement occurred when Shepard developed Ménière's disease, an inner ear problem. Grissom was then moved to command Gemini 3. Slayton felt that Young was a better personality match with Grissom and switched Stafford and Young. Finally, Slayton tapped Cooper to command the long-duration Gemini 5. Again for reasons of compatibility, he moved Conrad from backup commander of Gemini 4 to pilot of Gemini 5, and Borman to backup command of Gemini 4. Finally he assigned Armstrong and Elliot See to be the backup crew for Gemini 5. The third rearrangement of crew assignment occurred when Slayton felt that See wasn't up to the physical demands of EVA on Gemini 8. He reassigned See to be the prime commander of Gemini 9 and put Scott as pilot of Gemini 8 and Charles Bassett as the pilot of Gemini 9. The fourth and final rearrangement of the Gemini crew assignment occurred after the deaths of See and Bassett when their trainer jet crashed, coincidentally into a McDonnell building which held their Gemini 9 capsule in St. Louis. The backup crew of Stafford and Cernan was then moved up to the new prime crew of Gemini 9A. Lovell and Aldrin were moved from being the backup crew of Gemini 10 to be the backup crew of Gemini 9. This cleared the way through the crew rotation for Lovell and Aldrin to become the prime crew of Gemini 12. Along with the deaths of Grissom, White, and Roger Chaffee in the fire of Apollo 1, this final arrangement helped determine the makeup of the first seven Apollo crews, and who would be in position for a chance to be the first to walk on the Moon.


Missions

In 1964 and 1965, two Gemini missions were flown without crews to test systems and the heat shield. These were followed by 10 flights with crews in 1965 and 1966. All were launched by Titan II launch vehicles. Some highlights from the Gemini program: * On Gemini 4, Ed White became the first American to make an extravehicular activity (EVA, or "spacewalk") on June 3, 1965. * Gemini 5 (August 21–29, 1965) demonstrated the 8-day endurance necessary for an Apollo lunar mission with the first use of
fuel cell A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requ ...
s to generate its electrical power. * Gemini 6A accomplished the first space rendezvous with its sister craft
Gemini 7 Gemini 7 (officially Gemini VII) With Gemini IV, NASA changed to Roman numerals for Gemini mission designations. was a 1965 crewed spaceflight in NASA's Gemini program. It was the fourth crewed Gemini flight, the twelfth crewed American spacefli ...
in December 1965, with Gemini 7 setting a 14-day endurance record for its flight. * Gemini 8 achieved the first
space docking Docking and berthing of spacecraft is the joining of two space vehicles. This connection can be temporary, or partially permanent such as for space station modules. ''Docking'' specifically refers to joining of two separate free-flying space ...
with an unmanned Agena target vehicle. * Gemini 10 established that radiation at high altitude was not a problem, further demonstrated the ability to rendezvous with a passive object, and was the first Gemini mission to fire the Agena's own rocket.
Michael Collins Michael Collins or Mike Collins most commonly refers to: * Michael Collins (Irish leader) (1890–1922), Irish revolutionary leader, soldier, and politician * Michael Collins (astronaut) (1930–2021), American astronaut, member of Apollo 11 and Ge ...
would be the first person to meet another spacecraft in orbit, during his second successful EVA. * Gemini 11 first direct-ascent (first orbit) rendezvous with an Agena Target Vehicle, docking with it 1 hour 34 minutes after launch. Set a crewed Earth orbital altitude record of in September 1966, using the Agena target vehicle's propulsion system. This record still stands as of 2022. *On Gemini 12, Edwin "Buzz" Aldrin became the first space traveler to prove that useful work ( EVA) could be done outside a spacecraft without life-threatening exhaustion, due to newly implemented footholds, handholds, and scheduled rest periods. Rendezvous in orbit is not a straightforward maneuver. Should a spacecraft increase its speed to catch up with another, the result is that it goes into a higher and slower orbit and the distance thereby increases. The right procedure is to go to a lower orbit first and which increases relative speed, and then approach the target spacecraft from below and decrease orbital speed to meet it. To practice these maneuvers, special rendezvous and docking simulators were built for the astronauts. File:Ed White with Space Gun maneuvering unit.jpg, Edward White during spacewalk, Gemini 4, June 1965 File:Gemini 7 in orbit - GPN-2006-000035.jpg, Rendezvous of Gemini 6A and 7, December 1965 File:The First Docking in Space - GPN-2000-001344.jpg, First docking; Agena target is seen from Gemini 8, March 1966


Gemini-Titan launches and serial numbers

The Gemini-Titan II launch vehicle was adapted by NASA from the U.S. Air Force Titan II ICBM. (Similarly, the
Mercury-Atlas Mercury-Atlas was a subprogram of Project Mercury that included most of the flights and tests using the Atlas LV-3B The Atlas LV-3B, Atlas D Mercury Launch Vehicle or Mercury-Atlas Launch Vehicle, was a human-rated expendable launch system u ...
launch vehicle had been adapted from the USAF
Atlas missile The SM-65 Atlas was the first operational intercontinental ballistic missile (ICBM) developed by the United States and the first member of the Atlas rocket family. It was built for the U.S. Air Force by the Convair Division of General Dyna ...
.) The Gemini-Titan II rockets were assigned Air Force serial numbers, which were painted in four places on each Titan II (on opposite sides on each of the first and second stages). USAF crews maintained Launch Complex 19 and prepared and launched all of the Gemini-Titan II launch vehicles. Data and experience operating the Titans was of value to both the U.S. Air Force and NASA. The USAF serial numbers assigned to the Gemini-Titan launch vehicles are given in the tables above. Fifteen Titan IIs were ordered in 1962 so the serial is "62-12XXX", but only "12XXX" is painted on the Titan II. The order for the last three of the 15 launch vehicles was canceled on July 30, 1964, and they were never built. Serial numbers were, however, assigned to them prospectively: ''12568'' - GLV-13; ''12569'' - GLV-14; and ''12570'' - GLV-15.


Program cost

From 1962 to 1967, Gemini cost $1.3 billion in 1967 dollars ($ in ). In January 1969, a NASA report to the US Congress estimating the costs for Mercury, Gemini, and Apollo (through the first crewed Moon landing) included $1.2834 billion for Gemini: $797.4 million for spacecraft, $409.8 million for launch vehicles, and $76.2 million for support.


Current location of hardware


Spacecraft

* Gemini 1: Intentionally disintegrated upon re-entry to the atmosphere * Gemini 2:
Air Force Space and Missile Museum The Air Force Space and Missile Museum is located at Launch Complex 26 at Cape Canaveral Space Force Station, Florida. It includes artifacts from the early American space program and includes an outdoor area displaying rockets, missiles, and spa ...
, Cape Canaveral Air Force Station, Florida * Gemini III: Grissom Memorial,
Spring Mill State Park Spring Mill State Park is a state park in the state of Indiana. The park is located to the south of Bloomington, about east of the city of Mitchell on Indiana Highway 60. It contains a settler's village, the Gus Grissom Memorial (with the ac ...
, Mitchell, Indiana * Gemini IV:
National Air and Space Museum The National Air and Space Museum of the Smithsonian Institution, also called the Air and Space Museum, is a museum in Washington, D.C., in the United States. Established in 1946 as the National Air Museum, it opened its main building on the Nat ...
, Washington, D.C. * Gemini V:
Johnson Space Center The Lyndon B. Johnson Space Center (JSC) is NASA's center for human spaceflight (originally named the Manned Spacecraft Center), where human spaceflight training, research, and flight control are conducted. It was renamed in honor of the late U ...
, NASA, Houston, Texas * Gemini VI:
Stafford Air & Space Museum The Stafford Air & Space Museum is located in Weatherford, Oklahoma, Weatherford, Oklahoma, United States. The museum, named for NASA astronaut and Weatherford native Thomas P. Stafford, became a Smithsonian Affiliations, Smithsonian Affiliate in J ...
, Weatherford, Oklahoma * Gemini VII: Steven F. Udvar-Hazy Center, Chantilly, Virginia * Gemini VIII: Armstrong Air and Space Museum, Wapakoneta, Ohio * Gemini IX: Kennedy Space Center, NASA, Merritt Island, Florida * Gemini X: Kansas Cosmosphere and Space Center, Hutchinson, Kansas * Gemini XI: California Museum of Science and Industry, Los Angeles, California * Gemini XII: Adler Planetarium, Chicago, Illinois


Trainers

* Gemini 3A: St. Louis Science Center, St. Louis, Missouri. * Gemini MOL-B: National Museum of the United States Air Force, Wright-Patterson Air Force Base, Dayton, Ohio * Gemini Trainer: Discovery Center, Fresno, California * Gemini Trainer: U.S. Space & Rocket Center, Huntsville, Alabama * Gemini Trainer:
Kentucky Science Center The Kentucky Science Center, previously known as the Louisville Museum of Natural History & Science and then Louisville Science Center, is Kentucky's largest science museum. Located in Louisville, Kentucky, on "Museum Row" in the West Main Distr ...
, Louisville, Kentucky * Gemini Trainer: Texas Air Museum, Slaton, Texas * 6165, GATV:
National Air and Space Museum The National Air and Space Museum of the Smithsonian Institution, also called the Air and Space Museum, is a museum in Washington, D.C., in the United States. Established in 1946 as the National Air Museum, it opened its main building on the Nat ...
, Washington, D.C. (not on display)https://airandspace.si.edu/collection-objects/target-adapter-agena
(Wayback Machine 2018-09-19)
* El Kabong: Kalamazoo Air Museum, Kalamazoo, Michigan * Gemini Trainer: Kalamazoo Air Museum, Kalamazoo, Michigan * TTV-2: National Space Centre, Leicester, UK * Trainer: Pate Museum of Transportation, Fort Worth, Texas * MSC 313: Private residence, San Jose, California * Rogallo Test Vehicle:
White Sands Space Harbor White Sands Space Harbor (WSSH) is a spaceport in New Mexico that was formerly used as a Space Shuttle runway, a test site for rocket research, and the primary training area used by NASA for Space Shuttle pilots practicing approaches and landin ...
, White Sands, New Mexico * TTV-1: Steven F. Udvar-Hazy Center, Chantilly, Virginia * unnamed:
Air Force Space and Missile Museum The Air Force Space and Missile Museum is located at Launch Complex 26 at Cape Canaveral Space Force Station, Florida. It includes artifacts from the early American space program and includes an outdoor area displaying rockets, missiles, and spa ...
, Cape Canaveral Air Force Station, Florida * unnamed:
Air Force Space and Missile Museum The Air Force Space and Missile Museum is located at Launch Complex 26 at Cape Canaveral Space Force Station, Florida. It includes artifacts from the early American space program and includes an outdoor area displaying rockets, missiles, and spa ...
, Cape Canaveral Air Force Station, Florida * Ingress/Egress Trainer: U.S. Space & Rocket Center, Huntsville, Alabama * MSC-307: USS ''Hornet'' Museum, former NAS Alameda, Alameda, California Gemini2x.jpg, ''Gemini 2'' at Air Force Space and Missile Museum in 2006 Gemini3 Capsule.jpg, ''Gemini III'' at Grissom Memorial in 2011 Gemini IV Capsule.jpg, ''Gemini IV'' at National Air and Space Museum in 2009 Gemini V Space Center Houston.JPG, ''Gemini V'' at Johnson Space Center in 2011 Gemini VI-A Oklahoma History Center.JPG, ''Gemini VI-A'' at Stafford Air & Space Museum in 2011 Gemini VII Capsule.jpg, ''Gemini VII'' at Steven F. Udvar-Hazy Center in 2009 Gemini VIII Capsule.jpg, ''Gemini VIII'' at Armstrong Air and Space Museum in 2010 Gemini IX-A Kennedy Space Center.JPG, ''Gemini IX-A'' at Kennedy Space Center in 2011 Gemini X Capsule.jpg, ''Gemini X'' at Kansas Cosmosphere and Space Center in 2010 Gemini 11 capsule (front) at California Science Center.jpg, ''Gemini XI'' at California Museum of Science and Industry in 2013 Gemini XII Capsule.jpg, ''Gemini XII'' at Adler Planetarium in 2010


Proposed extensions and applications


Advanced Gemini

McDonnell Aircraft, the main contractor for Mercury and Gemini, was also one of the original bidders on the prime contract for Apollo, but lost out to
North American Aviation North American Aviation (NAA) was a major American aerospace manufacturer that designed and built several notable aircraft and spacecraft. Its products included: the T-6 Texan trainer, the P-51 Mustang fighter, the B-25 Mitchell bomber, the F ...
. McDonnell later sought to extend the Gemini program by proposing a derivative which could be used to fly a cislunar mission and even achieve a crewed lunar landing earlier and at less cost than Apollo, but these proposals were rejected by NASA. A range of applications were considered for Advanced Gemini missions, including military flights, space station crew and logistics delivery, and lunar flights. The Lunar proposals ranged from reusing the docking systems developed for the Agena Target Vehicle on more powerful upper stages such as the Centaur, which could propel the spacecraft to the Moon, to complete modifications of the Gemini to enable it to land on the lunar surface. Its applications would have ranged from crewed lunar flybys before Apollo was ready, to providing emergency shelters or rescue for stranded Apollo crews, or even replacing the Apollo program. Some of the Advanced Gemini proposals used "off-the-shelf" Gemini spacecraft, unmodified from the original program, while others featured modifications to allow the spacecraft to carry more crew, dock with space stations, visit the Moon, and perform other mission objectives. Other modifications considered included the addition of wings or a parasail to the spacecraft, in order to enable it to make a horizontal landing.


Big Gemini

Big Gemini (or "Big G") was another proposal by McDonnell Douglas made in August 1969. It was intended to provide large-capacity, all-purpose access to space, including missions that ultimately used Apollo or the Space Shuttle. The study was performed to generate a preliminary definition of a logistic spacecraft derived from Gemini that would be used to resupply an orbiting space station. Land-landing at a preselected site and refurbishment and reuse were design requirements. Two baseline spacecraft were defined: a nine-man minimum modification version of the Gemini B called Min-Mod Big G and a 12-man advanced concept, having the same exterior geometry but with new, state-of-the-art subsystems, called Advanced Big G. Three launch vehicles-
Saturn IB The Saturn IB (also known as the uprated Saturn I) was an American launch vehicle commissioned by the NASA, National Aeronautics and Space Administration (NASA) for the Apollo program. It uprated the Saturn I by replacing the S-IV second stage (, ...
,
Titan IIIM The Titan IIIM was a planned American expendable launch system, intended to launch the Manned Orbiting Laboratory and other payloads. Development was cancelled in 1969. The stretched core stage was used on some versions of the Titan IIIB and the ...
, and
Saturn INT-20 The Saturn INT-20 was a proposed intermediate-payload follow-on from the Apollo Saturn V launch vehicle. A conical-form interstage would be fitted on top of the S-IC stage to support the S-IVB stage, so it could be considered either a retrofitted ...
(S-IC/S-IVB) were investigated for use with the spacecraft.


Military applications

The Air Force had an interest in the Gemini system, and decided to use its own modification of the spacecraft as the crew vehicle for the
Manned Orbital Laboratory The Manned Orbiting Laboratory (MOL) was part of the United States Air Force (USAF) human spaceflight program in the 1960s. The project was developed from early USAF concepts of crewed space stations as reconnaissance satellites, and was a succ ...
. To this end, the Gemini 2 spacecraft was refurbished and flown again atop a mockup of the MOL, sent into space by a Titan IIIC. This was the first time a spacecraft went into space twice. The USAF also had the notion of adapting the Gemini spacecraft for military applications, such as crude observation of the ground (no specialized reconnaissance camera could be carried) and practicing making rendezvous with suspicious satellites. This project was called
Blue Gemini Blue Gemini was a United States Air Force (USAF) project first proposed in August 1962 for a series of seven flights of Gemini spacecraft to enable the Air Force to gain manned spaceflight experience prior to the launch of the Manned Orbital Develo ...
. The USAF did not like the fact that Gemini would have to be recovered by the US Navy, so they intended for Blue Gemini eventually to use the airfoil and land on three skids, carried over from the original design of Gemini. At first some within NASA welcomed sharing of the cost with the USAF, but it was later agreed that NASA was better off operating Gemini by itself. Blue Gemini was canceled in 1963 by
Secretary of Defense A defence minister or minister of defence is a cabinet official position in charge of a ministry of defense, which regulates the armed forces in sovereign states. The role of a defence minister varies considerably from country to country; in som ...
Robert McNamara, who decided the NASA Gemini flights could conduct necessary military experiments. MOL was canceled by Secretary of Defense Melvin Laird in 1969, when it was determined that uncrewed spy satellites could perform the same functions much more cost-effectively.


In media

* Two Gemini capsules (codenamed "Jupiter" instead of "Gemini") are featured in the plot of the 1967 '' James Bond'' film '' You Only Live Twice''. * A modified one-person Gemini capsule is used to send an astronaut (played by James Caan) to the Moon in the 1968 film ''
Countdown A countdown is a sequence of backward counting to indicate the time remaining before an event is scheduled to occur. NASA commonly employs the terms "L-minus" and "T-minus" during the preparation for and anticipation of a rocket launch, and eve ...
''. * Gemini missions 4, 8 and 12 feature in the first episode of the
HBO Home Box Office (HBO) is an American premium television network, which is the flagship property of namesake parent subsidiary Home Box Office, Inc., itself a unit owned by Warner Bros. Discovery. The overall Home Box Office business unit is ba ...
series '' From the Earth to the Moon' *Like other US space programs, Gemini was covered in the 1985 PBS series " Spaceflight" * Some aspects of the Gemini program relating to astronaut Neil Armstrong were touched upon in the 2018 film '' First Man''. * Many episodes of the television show ''
I Dream of Jeannie ''I Dream of Jeannie'' is an American fantasy sitcom television series, created by Sidney Sheldon that starred Barbara Eden as a sultry, 2,000-year-old genie and Larry Hagman, as an astronaut with whom she falls in love and eventually marrie ...
'' featured launch pad and launch footage of various Gemini missions. * Gemini, is a layer 7 telecom standard named after the Gemini missions. Its non-standard port number, 1965, is a reference to the first mission date.


See also

* List of crewed spacecraft * Splashdown (spacecraft landing) * Timeline of hydrogen technologies *
US space exploration history on US stamps With the advent of robotic and human spaceflight a new era of American history had presented itself. Keeping with the tradition of honoring the country's history on U.S. postage stamps, the U.S. Post Office began commemorating the various events ...


References


Notes


Citations


Books

* * * * * * * * * Shayler, David J. ''Gemini'', Springer-Verlag Telos, 2001, *


Articles

* * * * * *
Project Gemini —A Chronology (NASA report SP-4002) (PDF format)

Gemini Midprogram Conference —Including Experiment Results (NASA report SP-121) —Manned Spacecraft Center —Houston, Texas, February 23–25, 1966
* Gemini Summary Conference (NASA report SP-138) —Manned Spacecraft Center —Houston, Texas, February 1–2, 1967


External links











(many of which are on-line)

{{Authority control Space program of the United States 1960s in the United States 1962 establishments in the United States 1966 disestablishments in the United States Gemini Human spaceflight programs Gemini
Gemini B The Manned Orbiting Laboratory (MOL) was part of the United States Air Force (USAF) human spaceflight program in the 1960s. The project was developed from early USAF concepts of crewed space stations as reconnaissance satellites, and was a s ...